I obviously don't own Harry Potter, just the main character, their adopted family and Alex. I might also make up some characters along the way but maybe not. Bellatrix Lestrange had a child but she couldn't look after them. She gave her up for adoption and a married couple with 2 children of their own took them in. When they turned 11, they got their Hogwarts letter- but it was addressed to Miss Black (they werent Rodolphos' child). Evelyn's adopted parents had kept them not being their actual blood child a secret, but realized they ought to tell them the truth. Their story begins at the start of the school year- well, in Diagon Alley.